Internal-combustion engine



March 27, 1928. 1,663,865

D. T. sco'rT INTERNAL COMBUSTION ENGINE Filed April 5, 192'? 2 sheets-sheet 1 Il! l l l/V VE N TOR A TTORNEYS March 27, 1928. 1,663,865

D. T. scoTT INTERNAL COMBUSTION ENGINE Filed April 5. 1927 y 2 Sheecs-Sheet 2 DAV/o THa/vl Scor-r ATTORNE YS Patented Mar. Z7, 1928.

AUN 151" vEl) TAIE'Sy Lesesaa- PATENT ao-F'Flcs.

DAVID THOMV'IS'COTT, OF'VANCO'UVER, BRITISHVCOLUMBIA, CANADA.

"INTERNAL-COMBUSTIO ENGINE.

Application filed Apri1'5,.1927, Serialv No. 181,218, and in Canada September 18, 1926.

My'invention relates to improvements in internal combustionengines having for.y its objectsthe provision of means whereby opposed pistons may be utilizedin a single cylinder without having recourse to the use of an endwise movable sleeve; toy provide a pair of Yconnecting rods for the lupper piston which are of sufficient length Vto reduce v,side thrust upon the wristipinsrthereof to permit of adequate cooling ofthe pistons through their directcontact with thecylinder walls andto provide-a construct-ion whereby an. engine of thieftype h'avingopposed pistonsl in a single .cylinder vmay vbe Y,of `,relatively short Y vertical length.

The invention consists essentially of `an engine basehavinga'crank shaft, a cylindei upon the base, and opposedl pistonsendwise movable therein having rrod connection to the crank shaft, kas will be more fully described in the following specification, in which f Fig. 1 is a longitudinal'sectional view4 of the engineshowing the `pistonsat the point of firing.l V Y Fig. 2'is a transverse? sectional view show,- ing the pistons at the `o'utereends of their strokes. c Y n Fig. `3 is aplan view -in section showing the radiating "fins 'on the upper piston` head.

In the drawingsli'ke characters of reference indicate-corresponding parts in each figure.

Thenumeral E1 indicates.y generally a crank case having vcrank-shaft bearings 2 and a vtop wall 3 from which a sleeve or cylinder exten sion 4 depends to form an additional guide to the lower piston. The topfw-all 3 is providedwithfapairof slottedopenings 5.

The numeral 6 indicates generally a water jacketed open ended cylinder having an annular passage 7 adjacent its upper end provided with upper and lower ports numbered 8 and 9 respectively, through which the partially compressed charge of air or combustible mixture is adapted to flow at prede'- terinined intervals.

The numeral 10 indicates a threaded aperture which is adapted to be fitted with a spark plug if the engine is to be run with gasoline or light fuels, or a tiring plug if heavy oils are to be used..

The numeral-11 indicates a plurality of ports (shown in dotted lines in Figure 1) which communicate with' an exhaust pipe or manifold 12.

vtain VVa desired compressim of the air to be admitted to jt-he working space between .the opposed pistons.

The numeral'18 indicates a plurality of Yports communicating with an inlet pipe 19 which may be fitted with a poppet valve if the fuel lis to be admitted with the air. The numeral 20indicates ay crank shaft having a cent-re crank pin 21 and a pair of side crank pins y22 which are set at an angle of 180 degrees from the crank pin 21.

The numeral l23 indicates a piston of the ordinary internal combustion enginetype having al wrist pin 24 and a connecting rod 25 mounted at its big end to the crank pin 21.

The numeral 26 indicates generally a piston slidably movable in the upper end of the cylinder andthe head 13 and is formed with a sleeve portion 27 having a piston head 28 adjacent its lower end, which is provided with ins29 on its upper surface which Vare adapted to dissipate some of the heat of the ring charge into the air or vapour admitted to the engine as it flows from the head through a plurality of ports 30 inthe sleeve portion 27 through the ports 8, the annular passage 7 and the ports 9 into the firing space of the cylinder` 6. The lower extremity of the sleeve portion 27 extends beyond the piston head 28 to form a. portion of the required compression space of the cylinder and is provided with rings 31 in the usual manner. The upper extremity of the sleeve is provided with an annular flange 32, the purpose of which will hereinafter appear.

The numeral 33 indicates an outer sleeve of suchinternal diameter to pass freely over the outer walls of the cylinder 6 and is provided at itslower end with a pair of trunnions 34.- which are secured thereto by any suitable means, and are fitted with a pair of connecting rods 35, the big ends of which are connected to thecrank pins 22. The upternal periphery with piston rings 36 which form a gas tight connection with the inner walls of the head 13. The upper end of the outer sleeve is also provided with an internal annular flange 37 for the purpose of forming a seat to which the flange 32 of the upper piston 26 is secured.

I may prefer to fit an'intake bye pass 38 extending from the inlet pipe 19'or on the engine side of the inlet valve, if such should be fitted, and leading upwards `through a suitable check valve 39 to a port 40 communicating with the upper extremity of the head 13 so that as the piston 26 descends air or mixture is drawn into the head 13 ythrough the port 40 in such reasonable quanstroke of the piston before the ports 18v would be opened. Having thus described the several parts of my invention I will now briefly explain its cycle when operated asa two stroke engine having its charge admitted in the-form of combustible gas and fired by a spark plug.

The upper piston 26 on descending past the intake ports 18 allows an inrnsh of combustible gas to the head 13, on theupstroke of the same piston this charge is lightly compressed between the piston head 28 and the cover 16 until the ports 3() of the sleeve portion 27 of the piston 26 register with the ports 8 of the cylinder 6 when the lightly compressed gas passes through the ports 8, the annular passage7 and the ports9 around the lower extremity of the piston and into the firing space ofthe cylinder, this flood of gas fills the 4firing space and in its downward flow causes the residue of the prior spentcharge to be ejected .through the exhaust ports 11. On the return or approaching movement ofthe pistons viz: the downstroke ofthe upper piston 26 andthe npstroke of the lower piston 23, exhaust ports 11 and the inlet ports 9 are` closed off and the gas is'compressed between the opposing piston heads, when by a suitable timing mechanism it is ignited by the spark plug l' fitted intoV theY aperturelO of the cylinder 6, thus consuming and expanding the charge and driving the pistons in opposite directions away from each other and imparting rotation to the crank shaft 20 through the connecting rods 35 and25. The final downward movement of the piston 23 uncovers the ports 11 to allow the spent gases to escape from the cylinder.

That- I claim as my invention is:

V1. A two stroke internal combustion engine Comprising a suitably journalled crank shaft having opposed crank pins, an open ended cylinder having a lower piston,'rod connected toV one of the crank pins, an intake head upon the cylinder, an upper piston having a head adjacent itslower extremity and beingendwise movable andin operativeengagement with the cylinder and theV intake head, said piston rod being 'connected to the other crank pin, said piston Yhead hav-.

ing radiating fins projecting upwardly into the intake head, means for bye-passing the mixture admitted to the intake head into the cylinderbetween the pistons,'means for igniting the same and for exhausting the products of combustion from the cylinder.

2. `In a two stroke internal combustionV engine having a crank shaft, opposed crank pins operatively connected to lowerandupper pistons endwise-movable within a cylsoV inder, an intake head upon the cylinder Y having ports communicating with an intake DAVID 'rnoM soo'rr, Y 

